He described it in his book De nova stella ( Latin for "concerning the new star"), giving rise to the adoption of the name nova.
Novae most often occur in the sky along the path of the Milky Way, especially near the observed Galactic Center in Sagittarius however, they can appear anywhere in the sky. Recurrent nova processes are the same as the classical nova, except that the fusion ignition may be repetitive because the companion star can again feed the dense atmosphere of the white dwarf. A few novae produce short-lived nova remnants, lasting for perhaps several centuries. The sudden increase in energy expels the atmosphere into interstellar space creating the envelope seen as visible light during the nova event and in past centuries mistaken as a "new" star. This atmosphere, mostly consisting of hydrogen, is thermally heated by the hot white dwarf and eventually reaches a critical temperature causing ignition of rapid runaway fusion. When the orbital period falls in the range of several days to one day, the white dwarf is close enough to its companion star to start drawing accreted matter onto the surface of the white dwarf, which creates a dense but shallow atmosphere. They are likely created in a close binary star system consisting of a white dwarf and either a main sequence, subgiant, or red giant star. They are all considered to be cataclysmic variable stars.Ĭlassical nova eruptions are the most common type. The main sub-classes of novae are classical novae, recurrent novae (RNe), and dwarf novae. All observed novae involve white dwarfs in close binary systems. Causes of the dramatic appearance of a nova vary, depending on the circumstances of the two progenitor stars. Saving Earth Britannica Presents Earth’s To-Do List for the 21st Century.Artist's conception of a white dwarf, right, accreting hydrogen from the Roche lobe of its larger companion starĪ nova (plural novae or novas) is a transient astronomical event that causes the sudden appearance of a bright, apparently "new" star (hence the name "nova", which is Latin for "new") that slowly fades over weeks or months.Britannica Beyond We’ve created a new place where questions are at the center of learning.100 Women Britannica celebrates the centennial of the Nineteenth Amendment, highlighting suffragists and history-making politicians.
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